An example of such a construction vehicle is disclosed in DE 20 2007 010 294 U1. The latter comprises a milling drum mounted on a vehicle frame and driven by a diesel engine. Disposed downstream of the diesel engine is a transmission for transferring the drive power to the milling drum and to other transmissions connected in parallel.
A fundamental problem with such construction vehicles relates to the extremely high degree of oscillation, vibration, or shaking which is generated by the milling tool and is referred to below in general as “vibration”. This vibration can spread to substantially the entire construction vehicle unless damping measures are taken. Thus, individual measures aimed at decoupling individual vehicle components from the milling tool are always taken. For example, DE 10 2007 028 812 A1 concerns the decoupling of the driver's cab from the vibration generated by the milling tool.
The vibration produces a considerable amount of stress on the vehicle components. In order to ensure the durability of the drive motor, hitherto an attempt has always been made to decouple the drive motor as far as possible from the milling tool in terms of vibration. A currently widespread option is the use of a pump transfer gear, as described in the aforementioned document DE 20 2007 010 294 U1. The transmission of drive power between the drive motor and the milling tool is then achieved, at least partially, exclusively via the hydraulic pressure of a hydraulic fluid. The known damping properties of such a hydraulic fluid are then sufficient for adequately damping critical vibration.
The use of pump transfer gears is still widespread. This may be due to the fact that with such a pump transfer gear, a power take-off is easily engaged by operatively connecting other hydraulic motors. The disadvantages of such pump transfer gears, however, reside in the fact that their efficiency is somewhat poor as well as in the fact that fluid is lost resulting from leakages inherent to such a transfer gear. The leakages furthermore prevent precise speed synchronization between individual drives. Moreover, a pump transfer gear is expensive to purchase and maintain. Only pump transfer gears having a rigid gear ratio are acceptable in terms of purchasing and maintenance costs.